The Light Attribute Node is used to specify parameters that are not contained in the light shader. For instance, several light shaders can use shadow maps; the Light Attribute Node can be used to generate these shadow maps. When there are Light Attribute Node attached to a light, 3Delight for Maya will do its best to extract relevant parameters from the Maya light node.
Light Attribute Node - Created empty
Light Attribute nodes are created empty. Attributes can be added and removed by using the Add / Remove Attributes button. Left-click on this button brings up the The Add / Remove Attributes Window, which is better suited for multiple attribute additions or removals. Right-click on the Add / Remove Attributes button offers the same functionality through popup menus, which are more convenient when only one attribute or attribute group needs to be added or removed.